1. Field of the Invention
The present invention relates to an assembly for mounting a scraper blade beneath the undercarriage frame of a vehicle, and more particularly, to a mounting assembly structure which supports and permits adjustable positioning of the scraper blade in a variety of different positions relative to the surface to be scraped.
2. Description of the Prior Art
There are a variety of known arrangements for mounting a scraper blade to the underbody of a vehicle. Their mechanisms vary widely in structure and also in the way in which the scraper blade can be adjusted and positioned so as to perform the scraping task. In the more basic arrangements, the scraper blade is limited by its mounting structure to certain modes of movement. Typically, the scraper blade can be rotated around an axis which is vertical to the vehicle frame, thereby permitting the scraped material to be displaced to either side of the vehicle. Such arrangements also typically permit the blade to be rotated around a horizontal axis passing through the upper edge of the blade, whereby the lower edge of the blade can be rotated into or out of contact with the surface to be scraped. In another variation of this basic underbody mounting arrangement, the blade or the blade and its mounting assembly can be moved up and down in the direction of the vertical rotational axis. Examples of mechanisms of these general types appear in the following U.S. Pats.: E. Weeks, No. 1,760,926; E. Weeks, No. 1,878,080; Price, No. 1,932,601; Schermerhorn, No. 1,966,936; Tift, No. 3,517,753; W. Weeks, No. 3,355,825; and Dean, No. 1,793,066.
The basic scraper blade mounting assembly described in the preceding paragraph appears in other prior art embodiments with additional structure designed to introduce additional degrees of freedom of movement of the blade. These additional degrees of freedom are usually obtained by introducing structures which increase the number of axes of rotation for the blade or by adding means for translating the blade in the direction of one or more axes of rotation. The additional degrees of freedom can make the blade more flexible for handling different scraping tasks. For example, by permitting the blade to be angled relative to the horizontal plane of the vehicle frame, a "cornering" effect is developed which permits greater scraping effect to be concentrated at certain areas of the blade. This is particularly useful for scraping surfaces which are curved or otherwise nonplanar and for surfaces in which the material to be scraped is of nonuniform consistency, necessitating greater scraping force in some areas than in others. One known underbody scraper blade mounting assembly designed to accomplish this is disclosed in U.S. Pat. No. 2,238,389 to Kerber. A second such mounting structure developed for use with a grader machine rather than for undervehicle mounting is shown in U.S. Pat. No. 3,444,936 to Page, et al.
As can be noted from the disclosures of the Kerber and Page patents, prior art structures which introduce the additional degrees of freedom of movement necessary to perform cornering are complex. In addition, they may not be suitable for undercarriage frame mounting. Because of the complexity of the mechanical structures of these prior art structures, both the original and maintenance cost of scraper blade mounting assemblies of this design can be high. Moreover, it is obviously desirable to avoid the necessity of a special grader machine for such scraping tasks, because such devices cannot easily be equipped to carry a large load of sand or other material which, in snow scraping applications, may be spread on the scraped surface simultaneously with scraping.